PDF(Pubmed)
Abstract：
The Arabidopsis thaliana FLAGELLIN-SENSITIVE2 (FLS2), a typical receptor kinase, recognizes the conserved 22 amino acid sequence in the N-terminal region of flagellin (flg22) to initiate plant defense pathways, which was intensively studied in the past decades. However, the dynamic regulation of FLS2 phosphorylation at the plasma membrane after flg22 recognition needs further elucidation. Through single-particle tracking, we demonstrated that upon flg22 treatment the phosphorylation of Ser-938 in FLS2 impacts its spatiotemporal dynamics and lifetime. Following Förster resonance energy transfer-fluorescence lifetime imaging microscopy and protein proximity indexes assays revealed that flg22 treatment increased the co-localization of GFP-tagged FLS2/FLS2S938D but not FLS2S938A with AtRem1.3-mCherry, a sterol-rich lipid marker, indicating that the phosphorylation of FLS2S938 affects FLS2 sorting efficiency to AtRem1.3-associated nanodomains. Importantly, we found that the phosphorylation of Ser-938 enhanced flg22-induced FLS2 internalization and immune responses, demonstrating that the phosphorylation may activate flg22-triggered immunity through partitioning FLS2 into functional AtRem1.3-associated nanodomains, which fills the gap between the FLS2S938 phosphorylation and FLS2-mediated immunity.
摘要：
拟南芥FLAGELLIN-Sensitive2(FLS2),一种典型的受体激酶，识别鞭毛蛋白（flg22）N端区域的保守22个氨基酸序列，以启动植物防御途径，在过去的几十年里被深入研究。然而,flg22识别后质膜上FLS2磷酸化的动态调节需要进一步阐明。通过单粒子跟踪,我们证明，在flg22处理后，FLS2中Ser-938的磷酸化会影响其时空动力学和寿命。在进行Förster共振能量转移-荧光寿命成像显微镜和蛋白质接近指数分析后，发现flg22处理增加了GFP标记的FLS2/FLS2S938D的共定位，但没有增加FLS2S938A与AtRem1.3-mCherry的共定位，富含固醇的脂质标记物，这表明FLS2S938的磷酸化会影响FLS2对AtRem1.3相关纳米域的分选效率。重要的是,我们发现Ser-938的磷酸化增强了flg22诱导的FLS2内化和免疫反应，证明磷酸化可以通过将FLS2划分为功能性AtRem1.3相关的纳米结构域来激活flg22触发的免疫，填补了FLS2S938磷酸化与FLS2介导的免疫之间的空白。
